Ballistic armor

ABSTRACT

Ballistic armor for providing ballistic protection from an impacting projectile threat. The armor comprises a plurality of composite armor units. Each unit comprises a ceramic body having a cylindrical body portion with two end faces, one of which is adapted to face said threat. Each unit further comprises a non-ceramic belt member assembled with the ceramic body so that said member contiguously surrounds the cylindrical body portion without covering the one end face.

FIELD OF THE INVENTION

[0001] This invention relates to ballistic armor and, in particular, tosuch armor comprising ceramic bodies.

BACKGROUND OF THE INVENTION

[0002] It is known in the art to provide composite armor plates with aplurality of juxtaposed ceramic bodies such as tiles, cylinders, orspheres in order to protect against impacting ballistic threats.

[0003] U.S. Pat. No. 3,616,115 discloses a composite armor platecomprising successive layers of small discrete ceramic blocksencapsulated within a metal matrix by solid-state diffusion bonding. Theceramic blocks are maintained under compression in order to increase theamount of energy required by an impacting projectile to shatter theblocks.

[0004] U.S. Pat. No. 5,361,678 discloses composite armor comprisingceramic spheres embedded in a metal matrix. The spheres are fully coatedwith a binder and ceramic particles in order to insulate them fromthermal shock waves produced by the molten matrix during the embeddingstage, as well as to enhance the ballistic performance of the armor.

[0005] U.S. Pat. No. 6,112,635 discloses a composite armor plate forabsorbing and dissipating kinetic energy from a high velocity,armor-piercing projectile, the plate comprising a single layer ofceramic cylinders arranged in a plurality of adjacent rows. Thecylinders are in direct contact with each other and are bound by asolidified material.

SUMMARY OF THE INVENTION

[0006] The present invention suggests ballistic armor for providingballistic protection from an impacting projectile threat, the armorcomprising a plurality of composite armor units, each comprising aceramic body having a cylindrical body portion with two end faces, oneof which is adapted to face said threat, and a non-ceramic belt memberassembled with said ceramic body so that said member contiguouslysurrounds said cylindrical body portion without covering said one endface.

[0007] Preferably, each composite armor unit according to the presentinvention is bound to other such units by a binding material to form thearmor. The armor preferably further comprises a backing layer as isknown in the art for trapping fragments of the armor ejected by theimpact of the projectile threat.

[0008] The cylindrical body portion of the ceramic body, from which thecomposite armor unit of the present invention is assembled, may havedifferent cross-sectional shapes such as e.g. circular, polygonal, orthe like.

[0009] The end faces of the ceramic body may be flat, and one maythereby constitute a base for the body portion. As additional examples,the end faces may be convex, bulging away from the body portion, or theymay be concave, dipping into said portion. Various such designs mayenhance the ballistic performance of the armor or yield otheradvantages. The two end faces may not necessarily be of the same design.

[0010] The ceramic body of the composite armor unit according to thepresent invention may be made of any known armor ceramic material, suchas Alumina, Silicon Carbide, Silicon Nitride, Boron Carbide, or anyother refractory material such as ceramic glass and the like. A ceramicmaterial containing reinforcing fibers, as known in the art, may also beused.

[0011] The belt member, assembled with the ceramic body in accordancewith present invention, has an outer perimeter, and an inner perimeterdefining a hollow region to receive and adjoiningly surround the ceramicbody to fit about its cylindrical portion. The inner perimeter of thebelt member is designed to conform to the shape of said cylindrical bodyportion to enable the member to closely hug the body after assembly. Theouter perimeter of the belt member may be of any design and itsdimensions and/or shape may vary along the height of the belt member.

[0012] The belt member according to the present invention advantageouslyallows for a variety of possible shapes and sizes for its outerperimeter. For example, the outer perimeter of the belt member may becircular, elliptical, rectangular, otherwise polygonal, or may have anirregular shape but it is preferable that it have a simple geometry tofacilitate its manufacture. Such possibilities allow the composite armorunit and the ballistic armor of the present invention to be suited to awide range of needs. For example, the belt member may have a hexagonalouter perimeter to allow the unit with which it is assembled to becontiguous with neighboring units in the armor, thereby eliminating theinterstices between the units and increasing ballistic immunity tosmaller projectile threats. As another example, in order to reduceweight of the unit, and therefore the armor, the belt member may haverecesses, such as holes or depressions, formed therein or may have athickness which varies along its height. In addition, the belt membermay not necessarily extend along the entire height of the cylindricalbody portion of the ceramic body with which it is assembled, but rathermay, for example, have a ring-like shape to simply adjoin the perimeterof the body at a certain height. The above two design possibilities mayboth be embodied together in the belt member when in the form of aspiral, for example. The spiral belt member may extend along themajority of the ceramic body with which it is assembled, with a spaceseparating successive turns of the spiral. In this way, the spiraldesign of the belt member serves to reduce the weight of the unitwithout sacrificing its ballistic performance.

[0013] The belt member of the present invention may be made of a varietyof materials so long as the belt member possesses a minimal amount oftensile strength, which is at least about 3 kg/mm². Possible materialsinclude but are not limited to metal alloys such as Aluminum, Titaniumand Steel alloys, composites TM such as glass, carbon and aramids,Kevlar™, high strength plastics such as Nylon, polycarbonates, andpolyamids, High Density Poly-Ethylene (HDPE) within various resins,carbon fibers and the like. The various resins may include simplefabric, winded fabrics, or mats reinforcement resins.

[0014] Calculations that will be presented below show that one of themain advantages provided by ballistic armor comprising composite armorunits according to the present invention, is a much desired geometricalweight reduction per unit area of armor. To maximize this advantage, theaverage density of the belt member should be less than that of theceramic material from which the body is made. The average density of thebelt member depends not only on the material from which it is made, butalso on its design. Providing the belt member with depressions asmentioned above, for example, would serve to reduce its average density.

[0015] The geometrical weight reduction enabled by the present inventionis achieved by providing each of the composite armor units, from whichthe armor is composed, with a belt member of such a design as to reduceeach unit's average density without decreasing its ballisticeffectiveness. Determination of the optimal design of the belt membermay be made by computer calculation and simulation or by trial anderror, bearing in mind the nature of the expected threat from whichballistic protection is desired, in particular the types, calibers,ranges, and inclinations of the impacting projectiles. In general, themost important parameter to consider in selecting such a design is themaximal thickness t of the belt member.

[0016] It is clear from the above that the maximal possible reduction inthe average density of the composite armor unit and the ballistic armorof the present invention is dictated by the necessity to keep theballistic performance of the armor at a high level so that it mayprotect against the expected impacting projectile threat. Indefinitelyincreasing the thickness t of the belt member will surely further reducethe weight of the armor but at some point, ballistic performance willalso be compromised. It was found that both significant geometricalweight reduction is achieved and high ballistic performance ismaintained so long as the thickness t of the belt member does notsurpass about 10% of the ceramic body's diameter D.

[0017] The minimal reduction of the average density or weight of thebody that would still be considered essential is limited by the need tojustify the costs of manufacturing a belt member according to thepresent invention. Thus, while the provision of a belt member having athickness of 0.01%, for example, of the diameter D of the ceramic bodywould also render the composite armor unit lighter to some minor extent,this would not constitute an essential reduction in the unit's averagedensity as it is not sufficiently beneficial to justify such a beltmember's manufacture. In general, a belt member having a thickness t ofat least about 1% of the diameter D would be considered an essentialreduction.

[0018] The composite armor unit of the present invention employed inballistic armor provides additional advantages, which increase thearmor's ballistic effectiveness. Firstly, the belt member of the presentinvention confines the cylindrical body on which it is mounted so thatupon a projectile's impact on the body, the member radially resists anddelays ceramic fracture of the body outwardly towards the member'sperimeter and also applies resistance forces, which prevent penetrationof the projectile. In addition, the belt member provides separationbetween the cylindrical bodies, which along with the radial confinementit affords, prevents one body's ceramic fracture due to projectileimpact from affecting neighboring bodies. In order to enhance these twoadvantages, the belt member may be assembled with the body so as to hugthe body tightly providing it with inward radial compression, therebyincreasing resistance. Both of the above advantages increase the armor'smulti-hit capability, allowing it to withstand a plurality of projectileimpacts while maintaining high ballistic performance. In certaincircumstances, the latter advantages may be crucial to the point ofbeing preferable over a reduction in weight, in which case heaviermaterials may be used to form the belt members in order to enhanceballistic performance at the expense of geometrical weight gain.

[0019] The ballistic armor of the present invention is preferablyassembled from a single layer of composite armor units, but may also beformed from a plurality thereof. The composite armor units may or maynot be in direct contact with each other. The ballistic armor ispreferably in the form of a plate and may be curved to allow it toconform to various surfaces whose ballistic protection is desired. Thebinding material used to hold the units together may be any knownsuitable material such as thermoset plastic (e.g. epoxy resin orpolyurethane) and thermoplastic material (e.g. polyester, polycarbonate,polyamid). The backing layer of the ballistic armor in accordance withthe present invention serves to trap ceramic fragments as well as theresidual deformed projectile or fragments thereof, resulting from itsimpact and penetration. The backing layer may be made of any suitablematerial known in the art, e.g. aluminum, woven or unidirectional fabriclaminates comprising Spectra®, Dyneema®, Kevlar™, Twaron™, S₂ or E glassfibers, HDPE, aramids and the like within various resins. The armorpreferably also includes a cover material, such as a frontal spallcover, to cover and seal the front of the armor and to keep the units inplace, as well as to minimize outward deflection of the impactingprojectile threat, fragments of the threat or the units resulting fromimpact and/or other frontal debris. The cover material is preferablymade from layers of fibers, such as Kevlar™ and fiberglass, saturatedwithin thermoplastic and thermoset resins.

[0020] The ballistic armor according to the present invention mayfurther include an intermediate layer, as known in the art, between thecomposite armor units of the present invention and the backing layer toprovide a stand-off distance, enhancing the ballistic effectiveness ofthe armor. Such an intermediate layer may have any design, such as acellular honeycomb arrangement, and may be made of any appropriatesubstance, such as foamed materials. Other components known in the artto be used in composite ballistic armor technology may also be added tothe armor of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to understand the invention and to see how it may becarried out in practice, a preferred embodiment will now be described,by way of non-limiting example only, with reference to the accompanyingdrawings, which are not necessarily drawn to scale and are providedmerely for the purpose of illustration, include:

[0022]FIG. 1 is ballistic armor according to the present invention;

[0023]FIG. 2A is a ceramic cylinder used in composite armor technologyas known in the art;

[0024]FIG. 2B is a cross-section of an armor plate as known in the artcomprising ceramic cylinders of the kind shown in FIG. 2A;

[0025]FIG. 3A is a composite armor unit according to the presentinvention;

[0026]FIG. 3B is a cross-section of a piece of ballistic armor shown inFIG. 1 according to the present invention;

[0027]FIG. 4A is another embodiment of the composite armor unit inaccordance with the present invention;

[0028]FIG. 4B is a cross section of the composite armor unit shown inFIG. 4A;

[0029]FIG. 4C is yet another embodiment of the composite armor unit inaccordance with the present invention;

[0030]FIG. 4D is a cross section of the composite armor unit shown inFIG. 4C;

[0031]FIG. 4E is yet another embodiment of the composite armor unit inaccordance with the present invention;

[0032]FIG. 4F is a cross section of the composite armor unit shown inFIG. 4E;

[0033]FIG. 4G is yet another embodiment of the composite armor unit inaccordance with the present invention;

[0034]FIG. 4H is a cross section of the composite armor unit shown inFIG. 4G.

DETAILED DESCRIPTION OF THE INVENTION

[0035]FIG. 1 shows a section of a ballistic armor 30 according to thepresent invention for providing protection from an impacting projectilethreat P. The armor 30 comprises a plurality of composite armor units 32according to the present invention arranged in a single layer ofparallel rows. Each unit 32 is assembled from a cylindrical ceramic body34 having one flat end face and one convex end face adapted to face thethreat P, and from a belt member 36 mounted thereon in accordance withthe present invention. The belt member 36 is a thin-walled tube whosecircular inner and outer perimeters conform to the shape of thecylindrical ceramic body 34. Each belt member 36 contiguously surroundsone cylindrical ceramic body 34 to form one unit 32. The units 32 are indirect contact with each other forming interstices 38 therebetween. Theunits 32 are bound together by a binding material 40, which occupies theinterstices 38, as well as the periphery of the armor 30. The armor 30further includes a backing layer 42 covering the flat end faces of thebodies 34 on the rear side. On its front side, the armor 30 includes aspall cover 44 covering the convex end faces of the bodies 34 andsealing the units 32 in place.

[0036] The cylindrical ceramic bodies 34 are made by standard methods ofceramic manufacturing known in the art. The belt member 36 is producedin different ways corresponding to the material from which it is made.For example, for alloys of Aluminum, Steel, or Titanium, any knownmetallic production methods, such as extrusion, may be employed. Forbelt members 36 made of fiberglass, Kevlar™, or carbon, for example,filament-winding manufacturing methods are used. In any case, the beltmember 36 is made so that its inner diameter matches closely to thediameter D of the ceramic body 34 to allow it to be mounted thereon bysimple sliding.

[0037] To assemble the composite armor unit 32 according to the presentinvention, a single belt member 36 is mounted onto one ceramic body 34by hand or by machine.

[0038] The geometrical weight reduction achieved by the assembly of thebelt member 36 in the composite armor unit 32 according to the presentinvention can be best understood by comparing composite armor as knownin the prior art with ballistic armor 30 in accordance with the presentinvention.

[0039]FIG. 2A shows a typical, known ceramic cylinder 2 with a circularcross-section and one convex end face 4 adapted to face an impactingprojectile threat. FIG. 2B is a cross-section of a piece of compositearmor plate 6 comprising three ceramic cylinders 2 as shown in FIG. 2A,each cylinder 2 having a diameter D and being arranged in close contactas is known in the art and creating interstitial spaces 8 between them.The cylinders 2 are typically held in place by resins (not shown)occupying the spaces 8 and are covered by layers of ballistic fabric(not shown). Since they typically contain material lighter than ceramic,the interstitial spaces 8 serve to decrease the weight of the plate 6whilst being small enough not to reduce its ballistic performance.

[0040] A first imaginary equilateral triangle 10 may be considered byconnecting the centers of the three cylinders 2 in FIG. 2B. The triangle10 may be taken as a representative area for the entire plate accordingto which the ceramic cylinder's weight proportion η₀ may be calculated.Using the geometry of the triangle 10, it can be shown that:$\eta_{0} = {\frac{\pi}{2\sqrt{3}} = 0.906}$

[0041] Therefore, approximately 91% of the area of the plate 6 isoccupied by ceramic material, which is the plate's heaviest and mostabundant component. The interstitial spaces 8, which are fully orpartially filled with resin, constitute the remaining 9% of the plate'sarea.

[0042]FIG. 3A shows the composite armor unit 32 according to the presentinvention assembled from the ceramic body 34, which is similar to thecylinder 2 shown in FIG. 2A. The ceramic body 34 also has a diameter Dand includes the belt member 36 in accordance with the present inventionmounted thereon. FIG. 3B is a cross-section of a piece 46 of theballistic armor 30 shown in FIG. 1 comprising three composite armorunits 32 as shown in FIG. 3A, the units 32 being arranged and boundsimilarly to the cylinders 2 in FIG. 2A. The belt members 36 have athickness t and as a result each unit 32 has a diameter D+2 t, which islarger than that of cylinder 2. Consequently, interstice 38 is larger inarea than interstitial space 8.

[0043] A second imaginary equilateral triangle 48, may be considered byconnecting the centers of the three bodies 34 in FIG. 3B and may betaken as a representative area for the entire armor 30 according towhich the armor unit's weight proportion η may be calculated. Using thegeometry of the triangle 48, it can be shown that if × is a ratiobetween the thickness t of the belt member 36 and the diameter D of thebody 34, namely ×=t/D, then the armor unit's weight proportion η forbelt members 36 of average density ρ_(bm) and ceramic bodies 34 ofaverage density ρ_(cb) is $\eta = {\frac{\pi}{2\sqrt{3}} \cdot \phi}$

[0044] where the factor φ is given by:$\phi = \frac{1 + {4{x( \frac{\rho_{bm}}{\rho_{cb}} )}}}{( {1 + {2x}} )\sqrt{1 + {4x}}}$

[0045] It is clear from the above that when ×=0 (i.e. when there is nobelt member 36), then η=η₀.

[0046] The above calculations show that as long as the belt members 36have a lower average density than the ceramic cylindrical bodies 34(i.e. ρ_(bm)<ρ_(cb)), the factor φ will be a fraction and the armorunit's weight proportion η will be less than the ceramic cylinder'sweight proportion η₀ (i.e. η<η₀). The latter, in addition to theenlarged area of interstice 38 in comparison with interstitial space 8,renders the weight per unit area of armor 30 lower than that of theplate 6.

[0047] The following table shows an example of possible extents ofweight reduction as a function of the ratio x for ballistic armorcomprising composite armor units according to the present inventionassembled from a cylindrical body made from 98% Alumina (A₂O₃) andhaving an average density of ρ_(cb)=3.84 g/cm³, with a belt member madefrom an Aluminum alloy and having an average density of ρ_(bm)=2.75g/cm³ mounted thereon: Approximate weight χ Φ η reduction 0.01 0.9890.896 10% 0.02 0.978 0.886 11% 0.03 0.968 0.877 12% 0.04 0.958 0.868 13%0.05 0.949 0.860 14% 0.06 0.940 0.851 15% 0.07 0.931 0.843 16% 0.080.922 0.836 16% 0.09 0.914 0.828 17% 0.1 0.906 0.821 18%

[0048] As can be seen above, for a ratio × of 0.1, a weight reductionper unit area of about 18% over the plate shown in FIG. 2B can beachieved without a significant decrease in ballistic performance.

[0049] For a given projectile threat P, the number, size, shape, andarrangement of the composite armor units 32 in the ballistic armor 30 ofthe present invention yielding the optimal ballistic performance may beselected by trial and error. In the present example, the followingparameters have been used and results achieved for the units 32 arrangedas shown in FIG. 1, for successfully and repeatedly protecting from thethreat of 14.5 mm caliber API-B32 armor piercing bullets fired from anequivalent range of 250 meters, at an inclination of 0° (Nato) andhaving an impact velocity of 890 m/s):

[0050] Ceramic material of ceramic body—98% Alumina (Al₂O₃)

[0051] Density (specific gravity) of ceramic material: 3.84 g/cm³

[0052] Dimensions of cylindrical body: circular base of diameter D=19mm; height of 19 mm; convex spherical end faces having radii ofcurvature of R=31 mm.

[0053] Material of belt member: Al 6063T6

[0054] Thickness of belt member: t=0.7 mm

[0055] The armor plate in the form of an add-on module is bolted to a7.3 HHS (MIL-A-46100D) surface, for which enhanced ballistic protectionis desired. The plate includes a 10 mm Kevlar™ backing layer weighing 14g/m². It was shown that an armor plate with the above parameters weighs65 kg/M², in comparison to an identical competing plate (as in FIG. 2B)not employing the belt member of the present invention, which weighs 69kg/m². This considerable 5.8% decrease in weight is achieved without anyreduction in the plate's ballistic performance for the above threat aswell as for other projectiles. In fact, the ballistic performance isimproved by 10% as the multi-hit capability is found to yield a 90 mmspacing between shots, whereas the competing plate yields a 100 mmspacing between shots.

[0056] Clearly, various modifications within the scope of the compositearmor unit and ballistic armor according to the present invention may bemade. For example, FIG. 4A shows a composite armor unit 50 in accordancewith present invention assembled from a cylindrical body 51 with twoconvex spherical end faces and a belt member 52 mounted thereon having acircular inner perimeter to tightly surround the body 51, and ahexagonal outer periphery. The belt member 52 includes depressions 53formed therein to further reduce the average density of the member 52,and thereby the geometrical weight of the unit 50. A cross-section ofthe unit 50 is shown in FIG. 4B. In order to achieve extremely highballistic performance, such hexagonal units may be used in ballisticarmor to form a contiguous plate devoid of interstitial spaces. Thedepressions 53 aid to offset the gain in weight resulting from theabsence of the interstitial spaces.

[0057]FIG. 4C shows yet another embodiment of the composite armor unitaccording to the present invention. The unit 60 is assembled from asubstantially cylindrical body 61 having a hexagonal perimeter and twoflat end faces. The belt member 62 mounted on the body 61 has aring-like shape and does not extend along the entire height of the body61, but rather contiguously surrounds only a central portion thereof. Ascan be seen in the cross-section of the unit 60 in FIG. 4D, the member62 has both a hexagonal inner perimeter to conform to the body 61, and ahexagonal outer perimeter. The ring-like design for the belt member 62serves to further reduce the geometrical weight of the unit 60, but alsoallows for ballistic armor devoid of interstitial spaces and thereforehaving high ballistic performance.

[0058]FIG. 4E shows yet another embodiment of the composite armor unit70 according to the present invention. The unit 70 is assembled from acylindrical body 71 having one flat end face as its base and one convexend face adapted to face the projectile threat. The belt member 72,which has a circular inner and outer perimeter, includes indentations 73formed therein, as can be seen in a cross-section of the unit 70 shownin FIG. 4F. The indentations 73 serve to reduce the geometrical weightof the unit 70 without sacrificing ballistic performance. As is alsoshown in FIG. 4F, the belt member 72 is in the form of a cup withinwhich the body 71 sits. The belt member 72 extends to cover the base ofthe body 71 and includes a through hole 74 on its underside below thebase of the body 71. During assembly of the unit 70, the body 71 isplaced into the cup-shaped belt member 72 and pressed down until itsbase contacts the bottom of the member 72. Since the belt member 72contiguously surrounds the body 71, air occupying the cup-shaped beltmember 72 cannot escape along its walls when the body 71 is placedtherein, and therefore exits via the through hole 74 designed for thispurpose.

[0059]FIG. 4G shows yet another embodiment of the composite armor unit80 according to the present invention. The unit 80 is assembled from acylindrical body 81 having one flat end face as its base and one convexend face adapted to face the projectile threat. The belt member 82,which has a circular inner and outer perimeter, is in the form of aspiral. The member 82 is mounted on the body 81 and extends along amajority of its height. As is also shown by the cross-section of theunit 80 in FIG. 4H, spaces 83 present between successive turns of thespiral belt member 82 serve to reduce the geometrical weight of the unit80 without sacrificing ballistic performance.

[0060] It should be understood that the above described embodiments areonly examples of composite armor units and ballistic armor comprisingthem in accordance with the present invention, and that the scope of thepresent invention fully encompasses other embodiments which may becomeobvious to those skilled in the art.

1. A composite armor unit for providing ballistic protection from animpacting projectile threat, the unit comprising a ceramic body having acylindrical body portion with two end faces, one of which is adapted toface said threat, and a non-ceramic belt member assembled with saidceramic body so that said member contiguously surrounds said cylindricalbody portion without covering said one end face.
 2. A composite armorunit according to claim 1, wherein the ceramic body and the belt membereach has an average density such that the average density of said memberis lower than that of said body.
 3. A composite armor unit according toclaim 1, wherein the ceramic body is made from one of the following:Alumina, Silicon Carbide, Silicon Nitride, Boron Carbide, ceramic glass.4. A composite armor unit according to claim 1, wherein the belt memberis made from a material having a tensile strength of at least 3 kg/mm².5. A composite armor unit according to claim 4, wherein said material isa metallic alloy.
 6. A composite armor unit according to claim 5,wherein said alloy includes one of the following: Aluminum, Titanium,Steel.
 7. A composite armor unit according to claim 1, wherein the beltmember is made from one of the following: glass, carbon, aramids,Kevlar™, Nylon, polycarbonates, polyamids, High Density Poly-Ethylene,carbon fibers.
 8. A composite armor unit according to claim 1, whereinthe ceramic body has a diameter and the belt member has a maximalthickness, which is at most about 10% of said diameter.
 9. A compositearmor unit according to claim 1, wherein the belt member includesrecesses disposed therein.
 10. A composite armor unit according to claim1, wherein the belt member is in the form of a spiral.
 11. A compositearmor unit according to claim 1, wherein the belt member has a heightand thickness, which varies along said height.
 12. A composite armorunit according to claim 1, wherein the belt member is adapted to providethe cylindrical body portion with inward radial compression.
 13. Acomposite armor unit according to claim 1, wherein the belt member has acup-shape and is adapted to receive said ceramic body therein. 14.Ballistic armor for providing ballistic protection from an impactingprojectile threat, comprising a plurality of composite armor units asdefined in claim
 1. 15. Ballistic armor according to claim 14, furtherincluding a backing layer adapted to trap fragments resulting from theimpacting projectile threat.
 16. Ballistic armor according to claim 15,wherein said backing layer is made from one of the following: aluminum,Spectra®, Dyneema®, Kevlar™, Twaron™, High Density Poly-Ethylene,aramids, S₂ glass fibers, E glass fibers.
 17. Ballistic armor accordingto claim 14, further including a frontal spall cover adapted to trapfragments resulting from the impacting projectile threat.
 18. Ballisticarmor according to claim 17, wherein said spall cover is made from oneof the following: fiberglass, Kevlar™, themoset resin, thermoplaticresin.
 19. Ballistic armor according to claim 14, wherein said units arebound together by a binding material.
 20. Ballistic armor according toclaim 19, wherein said binding material is thermoset plastic. 21.Ballistic armor according to claim 19, wherein said binding material isa thermoplastic.